What do you mean when you say all other readings are low? Before we can give advice we need actual numbers. Your PH level shouldn't even be considered when determining whether or not to add more neons. I am not sure what the lady's concern was.I got 5 neon tetras for my aquarium and the lady said my pH was too high to be adding fish. It's been 2 days and the tetras seem to be doing just fine. How long before I can add a few more being sure they'll be fine in my tank conditions? My pH is generally around 8 all other readings are very low.
You said it better than me. TyI agree completely your tank isn't ready for fish and I am sorry your friend didn't help you more and told you to start this tank much sooner. Never rely on store employees for info unless it is a mom/pop store that the owners have raised fish for many years most "employees" haven't a clue about the stock. I have grands and great grands so I understand kids want everything and want them now. At 6 they are also old enough to understand you are still "building the fish house" and will want to help there. No way around the fact that if fish were in the future plans you should have started earlier with them. Sorry, but true. As you went ahead and bought the fish already, I suggest asking your friend who gave you some bacteria etc just not soon enough, if you can take the fish to his quarantine tank while yours cycles and let your child "visit" his fish? Also, sharks are not for most community tanks or only with larger fish as they can be aggressive also in research info. I agree with the advice to spend quality time with your child researching what is needed for the fish and it will benefit everyone and your child will get some study tips for later in school. Another thing I do is keep a small tank running in the corner of the room for a hospital tank in emergencies and a quarantine tank this is just an idea you might consider after getting your display tank up and running.
Since you brought a piece of cycled sponge from your friend's pond, you will have some beneficial bacteria in there that is if the sponge was kept moist to allow the beneficial bacteria to live. If your tank is still cycling, it probably means 1) the beneficial bacteria is still trying to catch up with your bioload, then feed less to the fish to give the BB in your filter a chance to catch up. 2) your bioload in the tank is too low compared to the pond, and the beneficial bacteria colony had crashed, then it is just a matter of reestablishing the nitrogen cycle, probably using the fish-in-cycle method. If that is the case, try to change the water more frequently and use API test to make sure the ammonia is converting to nitrate in a timely fashion. I think the most reasonable explanation might be two, then you just need to do fish in cycle.and a piece of sponge like material from his pond filter that I've added to mine.
Spoken from the heart and there is a wonderful lesson here as well to teach children... patience. Go slow and you won't be disappointing anyone, but more likely will have success!Having .25 ammonia. You shouldn't being adding fish at all. And especially at the rate you currently are. I understand it's hard to not want to disappoint a child on his bday. I think it would be more beneficial if you started the project slowly together and learning is the greatest gift and then reward of success. Sorry for being blunt. But these are living creatures. Not toys. Just imo. Sorry, not trying to offend, just inform.